1. Field of the Invention
This invention relates generally to the art of electrical connectors, and more particularly to an electrical connector assembly which includes a means for eliminating electrostatic discharge of static electricity in high-speed communication cables resulting from turbocharging.
2. Description of Related Art
A general well-recognized problem frequently encountered in cable-connected modular electronic systems results from a build-up of electrostatic potential between different components and their connectors. Electrostatic discharge (ESD) in such systems has the potential for causing deleterious results such as system malfunction or failure. Electronic computer systems having integrated circuits are particularly sensitive to such electrostatic discharges
Tribocharging is currently recognized as a significant problem in Local Area Networks (LANs). One popular networking option for connecting computers and equipment to LANs for high speed communication utilizes Unshielded Twisted Pair (UTP) cable and RJ45 connectors and jacks. Connections to a network are typically made to a female RJ45 jack by a male RJ45 connector. UTP cable typically consists of eight individually insulated, paired conducting wires which are collectively protected by a surrounding jacket. Each of the individual conducting wires has a terminal enclosed in an RJ45 connector or jack. Tribocharging is the buildup of static charge on the surface cable jacket during the reeling of the cable during installation or handling. Static charge on the charged jacket material of the cable having an attached RJ45 male connector induces a charge in the conductive wires of the cable which are in electrical contact with these terminal blades. When the charged RJ45 connector is inserted into the RJ45 jack, contact between the conductive terminals of the RJ45 connector and the conductive terminals of the RJ45 jack occurs, and electrostatic discharge to the LAN occurs. As mentioned previously, this discharge has the potential to damage sensitive components present in the network, and cause equipment malfunction and failure.
The problem of tribocharging went unrecognized until relatively recently because network failures were initially traced back to individual circuit packs containing integrated circuits sensitive to electrostatic discharge. Because the problem was solved by replacement of the circuit pack, system failures was attributed to manufacturing defects in the circuit packs.
A number of solutions for dealing with electrostatic discharge based on the general approach of providing a ground connection for an individual component or connector at risk have been proposed in the prior art, a number of representative examples of which follow. Biecher et al., in U.S. Pat. No. 5,478,253, describes an electrostatic discharge contact for blind mating connectors. Verdun, in U.S. Pat. No. 5,066,240, describes a high density electrical connector with electrostatic discharge protection. Northey and Sundy, in U.S. Pat. No. 5,409,387, disclose a connector with a passive switch for electrostatic discharge. St. Onge et al., in U.S. Pat. No. 4,814,698, discuss a technique for elimination of static in printed circuit board test fixtures. Other representative approaches are disclosed by Black et al., in U.S. Pat. No. 5,018,989 and Ziers, in U.S. Pat. No. 6,217,382. While effective, not all of these solutions are practical to implement in multiple component systems such as Local Area Networks because of cost and space constraints.
It is clear from the foregoing analysis that a serious need exists for a simple cost-effective space-saving connector assembly which eliminates or reduces the potential for electrostatic discharge (ESD) from high-speed communication cables. The present invention provides a solution to the problem not taught or suggested by the prior art.
Briefly described, the present invention comprises a connector assembly for removing static electricity generated in high-speed communication cable as a result of tribocharging. The present invention prevents damage to components such as integrated circuits which are sensitive to electrostatic discharge. The invention is realized with a high-speed cable having a connector with one or more conductive terminals, each of which terminates a conducting wire in the cable. In addition, the connector has one or more conductive pads, and a dissipative medium which electrically connects the terminals and pads. Static electricity on the jacket material of the cable induces a charge in the cable wire, which is bled from the terminals to the pads via the dissipative medium. A mating jack has a conductive pad electrically connected to ground for discharging the charge on the conducting pads of the connector before the terminals make electrical contact with matching terminals in the jack
The invention may be more fully understood by reference to the following drawings.